AT&T CEO Randall Stephenson recently responded to the rumor that Sprint would be getting the iPhone next month. During the Goldman Sachs Communacopia conference, Stephenson described the effect of carriers adding the iPhone as being “always overblown” by the media.

AT&T feels that the iPhone’s availability on more carriers does nothing, and will continue to do nothing, to the company’s relevancy among its competition. Stephenson said that, “I’m very confident that we’ll do very well with” the new iPhone…

“Anytime there’s another competitor launching Apple’s hit device, the expectations for what would happen to the carrier that had it before is overblown,” he continued, “The competitive dynamic will be no different than the last time.”

Stephenson also said that the iPhone 4 and 3GS are AT&T’s top-selling handsets. Only 40% of AT&T’s smartphone sales come from Blackberry and Android handsets. AT&T holds that its GSM iPhone is the only true “world phone,” as CDMA coverage is only available in the US. Verizon has claimed that the iPhone 5 will have dual-mode baseband support for operating overseas.

Stephenson also said that AT&T’s HSPA+ network provides “much faster network capability,” and that rival “iPhones will likely be 3G-only.”

The iPhone isn’t the only thing that AT&T has to offer, with Stephenson making the comments that Microsoft’s Windows Phone 7 was a “significant and meaningful player,” and that RIM is still “viable.”